Fig. 4.

SaeC is required for EsxB secretion. The top panel shows that mc²155 expresses and secretes EsxB into the culture supernatant (S). By contrast, in the mc²155ΔsaeC deletion strain, EsxB accumulates in the cell pellet (P), indicating SaeC is required for EsxB secretion. The esx1 deletion strain does not express EsxB. The lower panel demonstrates that GroEL (a marker for cytoplasmic proteins) was detected primarily in the cell pellet, indicating very little cell leakage occurred into the culture filtrate.